diff --git a/demo/65-page-sizes.ts b/demo/65-page-sizes.ts
new file mode 100644
index 0000000000..d6a9480c44
--- /dev/null
+++ b/demo/65-page-sizes.ts
@@ -0,0 +1,38 @@
+// Example of how to set the document page sizes
+// Reference from https://papersizes.io/a/a3
+// Import from 'docx' rather than '../build' if you install from npm
+import * as fs from "fs";
+import { convertMillimetersToTwip, Document, Packer, PageOrientation, Paragraph } from "../build";
+
+const doc = new Document({
+    sections: [
+        {
+            properties: {
+                page: {
+                    size: {
+                        orientation: PageOrientation.LANDSCAPE,
+                        height: convertMillimetersToTwip(210),
+                        width: convertMillimetersToTwip(148),
+                    },
+                },
+            },
+            children: [new Paragraph("Hello World")],
+        },
+        {
+            properties: {
+                page: {
+                    size: {
+                        orientation: PageOrientation.PORTRAIT,
+                        height: convertMillimetersToTwip(420),
+                        width: convertMillimetersToTwip(297),
+                    },
+                },
+            },
+            children: [new Paragraph("Hello World")],
+        },
+    ],
+});
+
+Packer.toBuffer(doc).then((buffer) => {
+    fs.writeFileSync("My Document.docx", buffer);
+});